SO much back and forth in this thread now even I am getting confused. Two different prodocts - the WiFiTrax ones with the 9 pin JST connector appear to be made to actually have the same pinout as the 9 pin DCC plug found on many locos. So they DO just plug in. It’s the LocoFi one that is backwards.
Names are too similar. The whole “WiFi” name for wireless networking is yet another one of the idiotic marketing things ever present int he computer industry. A stupid acronym that conveys exactly zero information on what the technology is. Wireless Fidelity? Only a marketing major who spent 4 years in college partying could come up with that junk. They claim it never stood for that, but the brand consulting firm that came up with it (yes, a company who’s sole purpose is to advise people on brand names for their products - what a world) says it was a play on HiFi audio, and that has always stood for High Fidelity.
Then the engineers go the opposite way, and just tack different letter suffixes after the base standard designation. Which one is better, a, b, n, ac, ax? So now the current top dog, 802.11ax, is being braded as WiFi 6. 802.11ac was retoractively named WiFi 5 for branding. So I guess that makes sense now, 6 comes after 5 and is an improvement on it, but on the cellular side we have 3G, 4G, and 5G. Nothing in sync. Leave off the outright lying from AT&T on which tech they actually are using for cell phones.
What does this have to do with trains? Not much, but the confusion of all these “*Fi” names gets the products all mixed up. WiFiTrax makes a controller for direct WiFi control of trains that is plug and play with the standard type of connector found in many DCC Ready locos. LocoFi makes a board with a common plug on it, but which does not directly plug in even though it’s the same plug. It doesn’t help that the LocoFi web site is wifimodelrailroad.com, further comfusing them with wifitrax.
If I may, the fundamental issue can be illustrated in a slightly different part of the car. Multiple DC circuits can be wired so either the ‘source’ or ‘sink’ of their voltage comes from one common point (to which a single common wire could be connected). In a car this is conveniently the whole mass of what used to be metal chassis and other structure, so you only have to run one wire to a device to be powered (the other connection being where it screws to the ‘common’.
Now’ like it or not, the electrons in DC current flow from the ‘negative’ to the ‘positive’ (by early convention too pedantic to give here) and so with negative ground the whole chassis becomes the ‘source’ of current with only the voltage-dropped return having to negotiate individual wires. Many British cars have positive ground, where the power goes out through the individual wires and only back to the battery through the common.
What Randy pointed out is that DCC assigned the ‘utility’ DC supply controlled by the decoder in a particular way, by standard – and this facilitated the use of standard connection plugs that one could assume would reasonably follow the standard. This is what LocoFi did not do that is the subject of this discussion.
In my opinion they could have avoided any concern by not using or touting a ‘NMRA standard’ plug if they wanted to wire that supply polarity backward. Instead they crawfish and try to make it as feature not a bug’. Randy pointed out early that the NMRA standard makes more objective sense electrically, so there was no performance reason they could assert.
By 6 I meant the maximum size of the recallable stack of locos that have recently been or are being run by one throttle. Digitrax double knob (that sounds a bit odd to anyone from the UK just btw) theoretically allows simultaneous control of two locomotives assuming sufficient dexterity and mental agility (or operating experience). Reading other threads suggested 6 operating locomotives in a throttle memory was some sort of limit for any given throttle.
Tech 6 handheld addon generates the command/control signals for up to 6 DCC locomotives. I thought there was a reason for choosing that number.
By running trains I really meant both running and controlling each train. Both DC and DCC allow for setting a train to run and then not trying to control it. By controlling I mean only paying sufficient attention to each train and then having the capability to exert control quickly enough. DC controllers are analog in two senses: haptic and electrical. DCC tend to be neither with the endless throttle controls and buttons with no direct ergonomic connection to the senses. Case in point, DC throttles indicate a position even when turned off, or should. DCC throttles generally don’t (one digitrax ive seen does and maybe Bachmann’s system does ). For example, my Tech 6 can be unplugged while preserving a throttle speed which is disconcerting if you forget to set the throttle to zero before you unplug it, or execute the stop or power off functions before unplugging the unit. You cannot tell you forgot just by looking at the throttle as you can with the Tech 7 product.
an NEC PowerCab can handle 6 locos. bear in mind that a single knob is not a good way to control multiple locos because you may have the knob set high for one loco and may not want it set that high when selecting another. the PowerCab uses buttons to control speed.
It is very specific to the system architecture - the stuff left up to the vendor, not controlled by the NMRA DCC specifications.
NCE throttles are limited to no more than 6 loco addresses per throttle. That’s in part because the cabs are really just dumb terminals, and all the information is held in the command station, and that’s all the memory it allows for. Even though the PowerPro command station can handle a LOT more than 6 locos, you need more throttles to go over 6. Not that controlling 6 locos from one throttle is really possible for one person to do.
Digitrax’s network works completely differently. There is no ‘recall’ because the information about which throttle is controlling which loco is stored in a completely different manner. If the command station is capable of 100 locos (DCS210 model) then I can theoretically use one throttle and start 100 different addresses running.
(just because you CAN - doesn’t mean you SHOULD< or that it’s even practical)
Issue 2 is the type of knob. The NCE ProCab/PowerCab use buttions and an encoder wheel as speed control options. The Digitrax DT-series throttles also use encoder knobs (and there are buttons as well). With these, you can easily switch back and forth between multiple locos and none of the change speed unless you actually turn the knob. The NCE Cab-06p and the Digitrax UT4 use potentiometer knobs. So if you have one loco running at 1/4 throttle, switch to another one and accelerate it to 3/4 speed, then switch back to the first one, you have to guess and get the knob close to the right position, or else the loco will speed up from 1/4 to 3/4. And vice-versa. Just another reason I don’t like potentiometer throttles. ESU solves this in the most typical German over-engineered way - their potentiometer knob is motorized, so when you switch to a different loco, the motor automatically dials the knob to whatever speed the loco is running.
Assuming I’m reading all this correctly the MRC Tech 6 handheld plug in throttle stores command/control information for up to six locomotives in a recall stack. It would have to work that way in order to operate “up to six” locomotives concurrently, all at potentially different speeds. The speed knob does not have a “setting” but only changes the speed of the locomotive address currently displayed (1-6). Recalling a different locomotive restores throttle control to that locomotive at the stored level as moving the throttle control knob only effects changes to the set speed. It creates a set speed for a specific address and does not create a set speed for that throttle immediately applicable to the locomotive being addressed.
I’m not sure why an operator would not want that as the default feature.
That’s why an encoder is preferred over a potentiometer when using recall stacks. Moving the knob or encoder wheel increases or decreases the speed from where the throttle was last set for the recalled locomotive rather than from a fixed point on the potentiometer knob.
There’s another way to handle switching between locos running at different speeds, but it would be the least desireable way possible to do it. I have no experience with MRC DCC so I have no idea how they do it, but they were rather late to the party as they had several DCC systems prior to their existing lineup that had little expansion capability - if you wanted/needed more, you tossed the old one and bought a new one. The other big players from the beginning designed their systems to allow you to start small and add on without having to discard your original investment.
That would be to just take the current throttle knob position as the speed. So you are running a loco at 3/4 speed. The knob is 3/4 of the way turned up from the stop position. You then recall a loco that you left running at 1/4 speed. The knob now assumes the curent position (physical, 3/4 of a rotation) is that 1/4 speed. Meaning you turn the knob back to the halfway (phycical) point and the loco stops, or you turn it to the 100% point (physically) and the loco now either runs at half speed, or it compresses the speed range of 1/4 to full into just 1/4 of the physical range of the knob. I really hope NO system does that, that’s absolutely horrible. None of the ones I am familiar with do.
But somewhere you have to take that into account - the the knod is at 3/4 and you select a loco running at 1/4, at some point the two have to be matched (remember, we are talking about potentiometer knobs here, where there is a fixed range of motion, usually 270-320 degrees). If you touch nothing, it’s fine, the loco can continue to move at the set speed. But at some point, either the command station has to poll the throttle, or the throttle has to send the current state to the command station. Or you touch the knob and turn it just a little. Having the loco adopt the throttle position is how most systems do it, ESU uses the motorized knob to physically turn the knob to match the speed.
I know next to nothing about the technical side of things, but …
My NEC powercab has both the thumb wheel and buttons to control speed. If I have a locomotive running at 20, and switch to one running at 40, the thumbwheel automatically runs at that speed. If you switch back, it’s at 20 again.
I would think could somehow be accomplished with a knob.
If I understand, that’s what Randy is talking about with a rotary encoder?
A common “real world” example of this is the volume knob in my car.
Whenever the car is started, the volume is always at 7 (this is programmable) no matter where the volume was when the car was turned off.
Since the volume knob is an encoder, and not a potentiometer, this is a simple matter of software coding.
I do not need to know how any of it works in order to adjust the volume of my radio. The whole system might even be very primitive, but none of that matters. It is a nice feature that works perfectly.
We would like to clarify some of the points made in some of the previous posts:
LocoFi™ modules DO NOT plug into the 8-pin DCC socket found on DCC ready locos (even if the wire connections were reversed and blue wire was made common positive). This is not a flaw. LocoFi™ is not DCC, was never meant to be. It’s a complete ground up approach to model railroading operations. However, we adhere to and provide NMRA color coded wires on our modules for easy identification. Because these wires don’t plug into DCC ready 8-pin socket, we don’t even provide the socket with our modules so that our users do not mistake it for plug’n’play into the DCC ready sockets and accidentally blow up the module. We clearly explain it in our install guides and videos to actually take out the DCC ready light board (from a DCC ready loco) and solder the wires as per NMRA color coding standard, wiring the blue to the negative side of LEDs and the white/yellow to the positive side of LEDs. It is probably worth an hour’s effort of installation for many hours of enjoyment yet to come.
To plug’n’play into a DCC socket, the LocoFi™ module will need to be designed that way, limiting the operating voltages to that of DCC. This will defeat the whole purpose of LocoFi™ being able to operate on a range of flexible DC voltages from as low as 7V to as high as 24V making it deadrail compatible for a variety of batteries as well. Yet, LocoFi™ runs well on DCC track power as well.
Ideally, an 8-pin plug should have been just that, an 8-pin plug where you can plug in ANY decoder or module of your choice. But, then you can’t make the loco work as a DC only board when the lights are LEDs. You need external circuitry to do that and that’s what the light board provides. Now,
